During the Franco-Prussian War of the late 19th century, Prussian forces invaded northern France. By September 18, 1870 Paris was completely surrounded and normal communications to the rest of France and the world were cut off. To facilitate the transmission of both military/diplomatic and civilian mail, a series of lighter than air balloon flights were organized where balloons would be flown out of Paris and landed hopefully beyond Prussian lines so the messages and mail could be transported to their destinations.
This folded letter traveled on the 30th such flight on a balloon named General Ulrich in honor of the French General who fought 48 days in an attempt to defend Strasbourg in August and September 1870. The balloon lifted off from Paris at 11:15 PM on the night of November 18. It flew in a cold rainstorm with only the mildest of variable breezes. It is thought that during the night it crisscrossed Paris several times as the winds reversed direction. At 8:00 AM on the 19th, the balloon landed near Luzarches a mere 20 miles north of Paris and still behind the Prussian lines. With the assistance of resident French peasants, the mail was snuck into the mail stream at the post offices of Luzarches and nearby Viarmes.
This letter was originally addressed to Neuchatel in Switzerland where it arrived on November 27, according to a back stamp. The addressee no longer being present, a new address label was affixed and the letter was forwarded on November 28 from Neuchatel to the general delivery office in Frankfurt Germany.